1. Code

#include <iostream>

using namespace std;

int main(void) {
    int a, b, c;
    cin >> a >> b >> c;

    cout << (a+b)%c << "\n";
    cout << ((a%c)+(b%c))%c << "\n";
    cout << (a*b)%c << "\n";
    cout << ((a%c)*(b%c))%c << "\n";
    return 0;
}

2. Result

        Runtime : 0 ms, Memory usage : 2016 KB
        (Runtime can be different by a system even if it is a same code.)

Check out the my GitHub repo for more info on the code. If you have questions, you can leave a reply on this post.